Process and device for the saccharification of cellulose and the like



H. scHoLLER Filed Dec.

M l "In F 3 HU R a 5 l3 HI IHHH" 3 3 3 Dec. 6,1932.

PROCESS AND DEVICE FOR THE SACCHARIFICATION OF CELLULOSE AND THE LIKEPatented Dec. 6', 1932 1,890,304

UNITED STATES PATENT OFFICE HEINRICH SCHOLLER, OF MUNICH, GERMANYPROCESS AND DEVICE FOR THE SACCHARIFICATION F CELLULOSE AND THE LIKEApplication filed December 6, 1927, Serial No. 238,195, and in GermanySeptember 7, 1927.

The present invention relates to a process spaces can be brought aboutby pressing the and device for the saccharification ofcellulosecellulose material or by filling the interstices and the like, withsolid, gaseous, foam-like substances on An economical solution of theproblem of mixtures of gas and percolating liquid, which saccharifyingcellulose involves high yields affords several advantages. For instance,if

at low consumption of acid; the extraction of twice the ordinaryquantity of cellulose ma.-

saccharine solutions of suitable concentraterial is stuffed into apercolator by pressing, tion, composition, and fermentability; simthefollowingsuperior features are evident plicity ofprocedure; and therecovery of the when comparing this method with a process lignineresidue in suitable form and its utiliusing no pressure: zation. 1) Thesaccharine solutions discharged Saccharification of cellulose resultingin show double concentration; high yields was hitherto possible only by(2) The same equipment and the same means of concentrated acids. Byapplying amounts of acid produce twice the amount of 15 the knownsaccharification processes employ-- sugar; ing diluted acids cellulosecan be degradated (3) The composition process is counterquantitativelyto grape sugar if the period acted as the sugar formed is dischargedfrom of hydrolysis is long enough, but the grape the percolator morerapidly-than at present. sugar thus formed is exposed to continual Thecellulose material can be pressed in decompositionso that the yield ispoor. dry or wet condition. If wet pressing is The process forming thesubject of the preferred. it is advisable to make a aste of presentinvention eliminates these decompoit by adding water and to place itinto the sit-ion processes by pressing the diluted acid. percolatorunder pressure, the cellulose re: through the cellulose material at highprcsmaining then pressed within the percolator sures and temperatures sothat the grape while the water runsofi. sugar forming is rapidlyremoved. In thecourse of saccharification the The decomposition of thegrape sugar soluamount of cellulose present in the percolator tionpressed out is prevented by neutraliza- 1s reduced resulting in turn ina reduction of tion cooling, release of pressure etc, the speed at whichsugar is being formed and The process of pressing the diluted acid alsoin a reduction in the concentration of through the cellulose material athigh presthe saccharine solution discharged. sures and temperatures isreferred to as per- In case'of cellulose material containing incolationor percolating saccharification, and Grusting matter the addition offresh celthe reaction vessels are referred to as percolulose material orfilling 0f the hollow spaces l tor with air eliminates thisdrawback onlypar- By applying the process according to this tially, while a bettermethod consists in workinvention a high and almost quantitative ing Withseveral percolators under the counyield i bt ined, ter-current processby letting the fresh acid Owing to its bulk cellulose material re-'enter first the most degradated material, then quires large rooms andlarge quantities of the semi-degradated and finally the newly acid sothat the saccharine contents of the added. Y

solutions obtained are quite low. For eco- Danger to the sugar alreadyformed is nomic reasons a higher sugar concentration is avoided byincreasing the velocity of flow of often desired which can be obtainedunder the the diluted acid. I new process without aflecting yield byreduc- Should this be impossible owing to the ing the size of theinterstices in the cellulose resistance of the pressed cellulosematerial,

material accessible to the acid and by exthe temperature of reaction orthe concenposing the material in this condition to per- ,trat on of theacid (hydrogen ion concentracolating saccharification. i tion) iscorrespondingly reduced so that the The reduction in the of-the hollowspeed at which sugar is formed and decomposed is lowered and thus thelonger period tion, preferably and suitably a part of the fermentedwort.

Accordin ly, alcohol-containing sugar solutions are cfiitained first andafterward, after their fermentation, increased concentrations ofalcohol.

The concentration of unstable sugar is replaced by concentration ofstable alcohol.

This measure can be employed in all cases where the product offermentation remains constant relative to the conditions of percolation.

As fermented wort usually contains small quantities of unattackablealbuminous substances of high molecular weight and polymericcarbohydrates which can be decomposed and made useful by means of acidhydrolysis, the employment of fermented wort as percolating liquid isprofitable also in this respect.

.To work on the counter-current principle with several percolatorsoffers special advantages also with regard to the effect andneutralization of the acid.

Cellulose material often possesses slightly neutralizing properties withthe result that the acid becomes saturated in the percolator which wasthe last to be filled with fresh raw material and to be subjected to theaction of the percolating liquid.

When using one battery the saturation of the acid is naturallyrestricted to the percolator through which it flows last so that theaction of the acid is unhampered in the other percolators.

If the saturating effect of the cellulose material is insuflicient toneutralize the acid in the last percolator, neutralization in thelastpercolator is brought about by suitable admixtures of a neutralizingcharacter added to the cellulose material. This eliminatesneutralization as a separate step in the process.

In addition to suitable concentration and neutral reaction of the sugarsolutions obtained the fermentation of the sugar juices and theproduction of east require contents of soluble nitrogen-phosphor-potashand magnesium compounds. In the interest of an economical application ofthe process organic and inorganic compounds of the nitrogen,phosphorous. potassium and magnesium should be added to the cellulosematerial before percolation to suit requirements, the

employment of said compounds being absorbed during percolation by thesaccharine solution formed so that the solutions discharged are adaptedto fermentation without further preparation.

By employing neutralizing fertilizing substances (tricalcium phosphate,ammonium carbonate, ammoniac, potassium carbonate, magnesium oxide,etc.) fertilization and neutralization of the juices can be combined.

The admixture of organic nitrogen and phosphorus acid carriers(acrospires, lupines) offers special'advantages in addition to the onementioned by producing, through percolation, a favorable effect upon thedegradation of the albuminous substances the dissolved constituent partsof which are removed from the system and thus protected againstdecomposition While the undissolved proteins are subjected to intensiveacid bydrolysis and, on the other hand, by saccharifying and makinguseful through percolation the starch, cellulose and hemicellulose oftheorganic nitrogen and phosphorus acid car- I1eI'S.

A satisfactory saccharification of a mixture of cellulose and starch wasimpossible by applying the usual starch and cellulose saccharificationprocesses employing diluted acids, because saccharification of starchtakes place many times more rapidly than that of the cellulose, and thesugar formed from starch decomposes during the intensive acid hydrolysisrequired for the cellulose. As percolation prevents the decomposition ofthe sugar, it is possible to saccharify cellulose mixed with othercarbohydrates that can be readily hydrolized and to obtain a good yieldfrom both.

Another feature of the invention of special importance for the problemof saccharification relates to the saccharification of cellulosematerial free from incrusting matter. In case of material containingincrusting matter filling up with cellulose material duringsaccharification is possible only within certain limits on account ofthe residual incrusting matter, while, on the other hand, during thepercolating saccharificat1on of cellulose material not containingincrustmg matter (cellulose dextrin) material of the same type may beadded contlnually, as the percolating saccharification leaves noappreciable residue.

In such cases the pasty cellulose material free from incrusting matteris preferably mixed with acid at high temperatures and continuallypressed into the percolator.

The charge of fresh cellulose material should be equal in quantity tothe saccharine solutions discharged to keep the amount of cellulosewithin the percolator uniform. The a battery of percolators can bedispensed with in this case.

For the purpose of saccharifying cellulose dextrin suitable filteringdevices attached to Cal the discharge side of the percolator will retainthe dispersed dextrin.

In place of a filter a suitable sieve may be used for fibrous cellulosematerial or for material containing incrusting matter.

Saccharine solutions obtained by percolation possess the property ofincreasing their contents of reducing and fermentable sugar bysubsequent acid hydrolysis, which is probably due to the presence ofcellubiosis. This subsequent hydrolysis of the sugar juices ispreferably caused by retarding the complete neutralization and cooling,and the subsequent hydrolysis should be continued until the maximumof'fermentable sugar has been reached. If complete neutralizationhappens to take place in the percolator through which the liquid hastrickled last, secondary hydrolysis should precede it.

The flow of diluted acid through a battery of percolators requires adrop of pressure, i. e. pressure in one percolator must be lower than inthe preceding one. If the operating pressure drops at any point in thebattery to the steam pressure of the percolating liquid, evaporationsets in which may lead to the complete decomposition of the sugar formedand the cellulose left over.

To avoid such troubles either the operating pressure should be chosenfrom the start materially higher than the steam pressure of thepercolating liquid or the steam pressure should be lowered by means of asuitable temperature drop in the direction of the flowing juices.Pressure above atmospheric can be produced only by pressure steam orcompressed air.

The economy of the process is further enhanced by the recovery of theheat contained in the juices discharged. For this purpose freshlyprepared acid (or cold water is guided in counter-current towards t esejuices so as to effect simultaneously cooling of the juices andpreheating of the acid (or water).

To reduce the cost of equipment acid is profitably added in a suitablemanner to the already preheated pressure water immediately before itenters thepercolator, whereby a considerable saving of acid-proofequipment and fittings is effected.

After saccharification is finished the percolators, aside from thelignine-like residue, contain the diluted and heated acid which can bepressed out of the percolator for further use without previousexpansion. By rinsing with (pressure) water the last remnants of acidcan be removed.

By the pressure release of the vessel a part of the heat contained inthe percolator is saved in the form of steam while, on the other hand,lignine is caused to drop off semidry, which increases its adaptabilityfor other uses.

The residues are to a large extent freed from the salts and resins ofthe original material by the percolating process and thereforeparticularly adapted for the production of ashless calorimetrically highgrade coal and active carbon, which is another point in favor of theeconomy of the process.

To produce active carbon it is profitable to impregnate the residueswhile still in the percolators with metallic salts and to car bonizethem after they are discharged.

The term cellulose and cellulose material cover wood, straw, peat, reed,leaves, moss etc.

The diluted acid solution used for percolation may consist of an organicor organic acids or acid salts or of mixtures of both substances.

One form of a device for applying the process described is shown in thedrawing, in which Figure 1 is a side view and Fig. 2 a top view. Thefresh water or fermented wort is sucked up by the pump 1 and forced intothe piping 2 provided with a heat exchanging vessel 3 which preheats theliquid while. on the other hand. it exercises a cooling effect upon theliquid circulating toward it, i. 0.. the subsequent saccharine solution.From the heat exchanging vessel 3 the piping 4 leads to the heater 5where the liquid'is heated to the desired high temperature and pressure.Behind the heater 5 is arranged a buffor vessel 6 connected with theheater 5 by the piping 7 From the buffer vessel 6 the piping 8 leads tothe battery of percolators. Behind the buffer vessel 6'is a check valve9 followed by the acid reservoir 10 connected with the piping 3 by anintermediate valve 11 adapted to regulate the amount of acid to beadded. The piping 8 ends in a system of pipes leading to thepercolator-s 12, 13. 14. 15. 16 and 17, whereupon it is continued aspiping 18 and ends in the heat exchanging vessel 3. The piping 19extends from the heat exchanging vessel and contains a flow regulatingdevice consisting of a throttle valve 20. After passing this valve theacid or neutral saccharine solution enters the storage vessels 21, 22,23 which can be opened and closed by the valves mentioned. The course ofthe acidified water through the battery of percolators can nowbecontinually regulated by connecting the percolators either separately orin series. the acid entering always the most degradatcd percolator andbeing discharged at the freshly filled one. Let us assume that 4percolators are working ata time and that they are to be continuallyconnected clockwise. In this ca the flow is as follows:

The acidified water flows through the pip-- ing 8 into the piping 24whose valve is open while the valves 25 and 26 of the side piping areclosed. as are the valves 27 and 28 of is provided third side piping isopen so that the acidified water flows through the pipings 8, 24 and 29to the percolator 12. After piping 30 whose valve is open while thevalve of the branch piping 31 is closed so that the liquid enters nowthe percolator 13. In the same way it flows through this percolator anden ters the open piping 32 whose side piping 33 is closed. Through thepiping 32 it flows into the percolator 14 and thence through the piping34 into the percolator 15. The side piping 35 of the piping 34is alsoclosed by a valve. From the percolator 15 the liquid enters the piping36 leading to the percolator 16, but as it is shut off here, the liquidenters the open side piping 37 and flows then through the piping 18-tothe heat exchanging vessel 3 and the discharge piping 19. The speed offlow is being regulated by the throttle valve 20. The more active theacid is, the greater may be the speed of flow; and the more spent theacid is, the slower will have to be the speed. Each percolator withsupply pipes 38 ending in a ring main 39 to make'it possible to feed thepercolator from the ring main too. For example, to fill the percolato'ranew, it is disconnected and the acidified water flows through thepipings 8, 39, 38 to the percolator 13. The percolator 16 is thenre-connected to the battery so that discharge takes place through thepipings 40, 41, 18. If the second percolator 13 is disconnected also,supply takes place through the ring main 39 and the arm 38 for thepercolator 14 while the return How is efiected by means of thepsercolator 17 and the discharge pipings 27,

I claim 1. The process of saccharification of cellulose materialcomprising, reducing the interstices in the. cellulose material bypressure, percolating diluted acid through the compressed cellulosematerial while heating the same under pressure, continually and, rapidlyremoving the solution of sugar formed from the system, and reducing thetemperature of the emerging sugar solution to prevent decomposition.

2. The process of saccharification of cellulose material comprising,reducing the interstices of the cellulose material by pressure,percolating diluted acid accordingto the counterflow principle throughthe compressed cellulose material while heating the same under pressure,continually and rapidlyremoving the solution of sugar formed from thesystem, and reducing the temperature of the emerging sugar solution toprevent decomposition.

3. The process of saccharification of cellulose material comprising,percolating diluted acid according to the counterflow principle throughthe cellulose material while heating the same under pressure, decreasingthe temperature of the diluted acid in progressive ratio when flowingthrough the gradually decomposed material, continually and rapidlyremovin the solution of sugar from the system, an reducing thetemperature of the emerging sugar solution to prevent decomposition. j

4. The process of saccharification of cellulose material comprising,reducing the interstices of the cellulose material by pressure,percolating diluted acid according to the counterflow principle throughthe compressed cellulose material while heating the same under pressure,reducing the temperature of the diluted acid in progressive ratio whenflowing through the gradually decomposed material, continually andrapidly removing the solu tion of sugar formed from the system, andreducing the temperature of the emerging sugar solution to preventdecomposition.

5. The process of saccharification of cellulose material comprising,admixing lime to the cellulose material, reducing the interstices of thecellulose material by pressure, percolating diluted acid according tothe counterflow principle through the compressed cellulose materialwhile heating the same under pressure, reducing the temperature of thediluted acid in progressive ratio when flowing through the graduallydecomposed material, neutralizing the diluted acid by lime contained inthe last traversed cellulose material, continually and rapidly removingthe solution of sugar formed from the system, and reducing thetemperature of the emerging sugar solution to prevent decomposition.

6. The process of saccharification of cellulose material comprising,admixing lime and calcium phosphate to the cellulose material, reducingthe interst ces of the cellulose material by pressure, percolatingdiluted acid according to the counterflow principle through thecompressed cellulose material while heating the same under pressure,reducing the temperature of the diluted acid in progressive ratio whenflowing through the gradually decomposed material, neutralizing thediluted acid by the lime combinations contained in the last traversedcellulose material, continually and rapidly removing the solution ofsugar formed from the system, and reducing the temperature of theemerging sugar solution to prevent decomposition.

7. The process of saccharification of cellulose mater al comprising,working up the cellulose in the presence of organic nitrogen compounds,reducing the interstices of the cellulose material bv pressure.percolating diluted acid according to the counterflow principle throughthe compressed cellulose material while heating the same under pressure,reducing the temperature of the diluted acid in progressive ratio whenflowing through the gradually decomposed material, continually andrapidly removing the solulSl tion of sugar formed and the organic nitrogen compounds in solution from the system, and reducing the temperatureof the emerging sugar solution to prevent decomposition. 8.- The processof saccharification of cellulose material comprising, working up thecellulose in the presence of starch, reducing the interstices of thecellulose material by pressure, percolating diluted acid according tothe counterflow principle through the compressed cellulose materialwhile heating the same under pressure, decreasing the temperature of thediluted acid in a progressive ratio when flowing through the graduallydecomposed material, continually and rapidly removing the solution ofsugar formed from the system, and reducing the temperature of theemerging sugar solution to prevent decompositlon. 2o 9. The process ofsaccharification of cellulose material comprising, reducing the inter!stices of the cellulose material by pressure, percolating with a mixtureof diluted acid and thoroughly fermented flavoring according to thecounterflow principle through the compressed cellulose material whileheating the same under pressure, decreasing the temperature of thediluted acid in a progressive ratio when flowing through the graduallydecomposed material, continually and rapidly removing the solutionofsugar formed from the system, and reducing the temperature of theemerging sugar solution to prevent decomposition. In witness whereof Ihave hereunto set my hand.

HEINRICH SCHOLLER.

